Transmission



Feb. 23, 1954 L, BROCK ET AL 2,669,880

TRANSMISSION Filed June 27, 1950 7 Sheets-Sheet l V' r I I O l h U (I I I I I I I l4 v a I I If I" HLB/QOCK O BY A. 6

Feb. 23, 1954 BRQCK AL 2,669,880

TRANSMISSION Filed June 27, 1950 7 Sheets-Sheet 2 HLBROCK J. RSTEl/ENSDA/ g 0 777INV NTORS BY ATTORNEYS 1954 H. BROCK ET AL 2,669,880

TRANSMISSION Filed June 27, 1950 7 Sheets-Sheet 3 hfLBROCK J RSTEVE/VSON INVENTORS ATTORNEYS Feb. 33, 1954 H. L. BROCK ET AL 2,669,880

TRANSMISSION Filed June 27, 1950 '7 Sheets-Sheet 4 H. L. BROCK J. RS TE 5 NS ON INVENTORS BY ELLA 62m ATTORNEYS Feb. 23, 1954 H. BROCK ET AL 2,669,880

TRANSMISSION Filed June 27, 1950 '7 SheetsSheet 5 H LBROC/f J. RSTEl/E/VSON F62 )77INVENTORS y ATTO/PNE VS Feb. 23, 1954 H. L. BROCK ET AL TRANSMISSION '7 Sheets-Sheet 6 Filed June 27, 1950 T LRU W H Feb. 23, 1954 H. L. BROCK ET AL TRANSMISSION Filad June 27, 1950 7 Sheets-Sheet 7 UJEAL 516257 LOW RANGE NE U TRAL L 0W RANGE LOW RANGE NEUTRAL LOW/RANGE RE1/ER5E LOW RANGE FOURTH HIGH RANGE /4 9 a/ REVERSE HR NGE 94 9 H G A ma /5/ M9 #1 /42 ,i'l,n /42 /2/ /53 /53 j 7%}. /2/

/57 X K /57 /56 /56 r- LOW RANGE HIGH RANGE HLBROC/f ELLUA RSTE g g 5 a MAO BY Q; 4 M

ATTORNEYS Patented Feb. 23, 1954- TRANSMISSION Harold L. Brock, Detro Ann Arbor, Mich., Company, Delaware it, and James R. Stevenson, assignors to Ford Motor Dearborn, Mich, a corporation of Application June 27, 1950, Serial No. 170,658

This invention relates generally to variable speed transmissions for motor vehicles.

The transmission of the present invention is particularly adapted for use in agricultural tractors, and an object of the invention is therefore to provide a transmission having a relatively large number of forward and reverse gear ratios in order that a suitable ratio will be available for each type of tractor operation. It is a further object of the invention to provide a. transmission obtaining the necessary speed ratios with a minimum number of gears and with a compact arrangement. In the present construction six forward and two reverse ratios are obtained with a transmission having only eleven gears compactly arranged upon four shafts so that the distances between the bearings for each shaft can be held to a minimum.

Another object of the invention is to provide a transmission in which gear ratios can be obtained for various operational requirements, with the proper steps being provided from a very low or creeping speed to a relatively high road or transport speed. In the present construction the speed ratios are not obtained in the usual manner of a step transmission in which, for example, a three speed transmission is provided with a reduction gear which can be inserted in the gear train to give a fixed reduction for each of the three regular speed ratios and thus provide a six speed transmission. While a transmission of this type is easily designed and manufactured, the six speed ratios thus obtained are necessarily in a mathematical progression and are not the proper ratios for the most efficient overall opera tion. While the present transmission provides two ranges in the shifting pattern, namely a low range and a high range, the ratios in the two ranges are not comparable to those of the usual step transmission, but are designed to provide the proper gear ratios for the various tractor operations. The particular design and arrangement of the gearing makes this possible.

Still another object of the invention is to provide simplified shifting mechanism enabling the transmission to be shifted between the various speed ratios easily and positively with a single gearshift lever.

Another object is to provide a shift pattern of a type generally familiar to the average individual and provided with visual indicating means enabling the tractor driver to tell at a glance the gear ratio the tractor is operating in at the moment and also the shift pattern to follow to reach any other desired speed range.

showing 8 Claims. (Cl. 74-360) Yet another object of the invention is to provide a transmission of the type mentioned in which positive interlocking means are provided to automatically hold inoperative the shift mechanism for all ratios other than that selected, and also to provide an interlocking arrangement preventing the engine starter from being applied except when the transmission is in neutral.

The foregoing and other objects of this invention will be made more apparent as this description proceeds, particularly when considered in connection with the accompanying drawings, wherein:

Figure 1 is a side elevational view of the rearward portion of a. tractor incorporating the transmission of the present invention, with parts broken away and in section.

Figure 2 is a transverse cross sectional view taken on the line 2-2 of Figure 1.

Figure 3 is an expanded cross sectional view of the transmission gearing, and comprises a section taken on the line 3-3 of Figure 2.

Figure 4 is an enlarged vertical cross sectional View of the transmission taken longitudinally through the transmission housing just inside the left hand side of the latter.

Figure 4A is a fragmentary cross sectional view through the rearward end of shift rail 91.

Figure 5 is a transverse vertical cross sectional view taken on the line 5-5 of Figure 4 and showing the shifter shaft in its uppermost position.

Figure 6 is a cross sectional view similar to a portion of Figure 5 but showing the shifter shaft in its intermediate or central position.

Figure 7 is a cross sectional view similar to Figures 5 and 6 but showing the shifter shaft in its lowermost position.

Figure 8 is a horizontal cross sectional view taken on the line 88 of Figure 5 showing the upper shift arm in position to shift the transmission between first and second speeds in low range. v

Figure 8A is a view similar to Figure 8 but the upper shift arm in position to shift the transmission between third and fifth speeds in high range.

Figure 9 is a horizontal cross sectional view taken on the line 9-9 of Figure 6, showing the upper shift arm in position to shift the transmission into low range neutral.

Figure 9A is a View similar to Figure 9 but showing the upper shift arm in position to shift the transmission into high range neutral.

Figure 10 is a horizontal cross sectional view taken on the line Iii-4t of Figure 7, showing "bolted together. .axle1.3"carryingroad-wheels I l at opposite sides the lower shift arm in position to shift the transmission between reverse and fourth speed in low range.

Figure A is a view similar to Figure 10 but showing the lower shift arm in position to shift the transmission between reverse and sixth speed in high range.

Figure 11 is a vertical cross sectional view taken on the line il-H of Figure 6 showing the upper interlock.

Figure 12 is a horizontal cross sectional view taken on the line l2-l2 of Figure 6, showing the lower interlock.

Figure 13 is a horizontal cross sectional :view taken on the line iii-l3 of Figure o showing-the starter interlock.

Figure 14 is a transverse cross sectional -view through the transmission taken on the line l l--i 4 of Figure 4.

Figure 15 is a front elevational view of the shift pattern plate.

shifting and interlocking mechanism.

Transmission gearing .Referringparticularly to Figures 1, 2 and3 of the drawing,.the rearward portion of the tractor chassis comprises-the clutch housing H and a transmission and rear axle housing i2 suitably 'Thehousing 12 supports a rear of the tractor. A spring supported seat 15 is mounted @upon housing .12 ,rearwardly of the-dash rIii-and steering wheel 8.

The transmission of the -,traetoriis mounted in the forward portionhof the housing t2, andcon- -ventional rear axle anddifferential mechanisms,

including a ring gear it of the hypoid type are mounted in the rearward-portion of the housing.

As best seen in Figures ,2 and 3, the transmission includes four longitudinally extending "shafts, namely a driveshaft2 l, acountershaft 22, a driven shaft .23, andan idler shaft 24. Inthe present construction the driveshaft 2| is in the form of a sleeve encircling a-power takeoff shaft which extends through the transmission to the rearward endof the tractorto-provide auxiliary for driving various implements and the like. sleeve'2l willbe termed adriveshaft.

The :driveshaft if is journaled at its forward end ina-bearing 271 supported in the front wall 28 of the housing l2 and the rearward end of thelshaft is journaledin a bearing 29 supported in :an .intermediatewall--31 extending transversely of the housing I2 and integrally formed therewith. Thedriveshaft 2| has a gear 32 formed integrally thereonnear its forward ,end. Rearswardlyof .the1gear;32 the driveshaftis formed with clutch -teeth 33, and rearwardly .of the clutch teeth 33 the driveshaft 2! is reduced in diameter :and rotatably supports a cluster gear 34 freely rotatable .upon thedriveshaft by'means of bushiings 135. Thecluster gear .35 has narrow. clutch,

teeth 31 formed at its forward end and is also :integrally :formed with axially spaced gears 38 andl3il.

The countershaft22 is likewise iournaled in bearings 4| and..42 supported in the transverse :walls Hand 3! of the transmission housing. At

the forwardendof theicountershaft22 a gear 43 is rotatably mounted. and.hastintegrally formed therewithnarrow clutch .teeth 44. :Also ifreely rotatably mountedupon thecountershaft122'is For the purposes of this .description the mounted in the transmission end being supported in the intermediate :wall 54 -,with:-narrow clutch teeth 68. gear 61a clutchimernberifi js-splinedto-thehub $4 of the gear 63.

.shaft 22.

The driven shaft 23 is positioned directly beneath the driveshaft 2| but is considerably shorter'in length 'since it supports only two gears .and a single clutch member.

The driven shaft 2'3is "journaledat its forward end in a bearing 53 supported'in an intermediate transverse wall .54. The;wa1l,,54 is integrally formed with the housing 12 and extends transversely across the lower'portion of the latter. The rearward portion of the driven shaft 23 extends through and us .icurnaled in bearings 56. supportedin an, offset portion of I the transverse wall 3 I of the housing.

.Rearwardly ;.0f the housing wall 3| the driven rshaftcarriesa drive pinion 51 of the, hypoidvtype which meshes with :the hypoid gear [-9 .;of the :rear axle mechanism. Adjacent thexforwardend -.of the driven shaft {23 the shaft rotatably sup- "ports a gear 58 having -f;ormed integrally there- :with narrow clutch :teeth :6 I .-.is,,-spline d "to the driven 'shaft 23 adjacent the 59. A clutch member gear 5,8,.and rearwardly-thereofa gear 162;is;fix-

i edly splined to the driven shaft.

The lowermostshaftin thetransmissionhousing is the idler shaft 24. This shaft is .fiXedly housin its. forwar of :the housing andiits rearward extremity being supported in and pinned to the wall ;3l ,of the housing. -!The:shaft isthus held 'againstgrotation. .Rutatably mounted upon the idler shaft -24 by means 40f bushings 1631s the hub :64 of ,a gear .66. A second a gear -51 j is rotatably mounted "upon' the hub 1B4 .of'the gear '63 vand is integrally formed Forwardly ofthe ,AlthoughjFigurefi is an expanded cross :sec-

:tionalview of the transmission gearing, ;all of the gears are shown inrtheir proper meshing engage- ;ment with-the exceptionof gear on counter- --shaft:'2;2;an1d.:geart1 oniidler shaft .24. In Figure i3 these two gears :are shown spaced fromeach other, .but ,it will Lbenoted from-the transverse cross :sectionalview of Figure 2that gears 50 and tlare actually in constant. mesh:with eachqother.

Bearing :this in-mind, Figure 3 can .be used-to trace the power flow :through the transmission gears-.i-nzthe,variousspeed-ratios.

Before tracing the power fiow however, the functionof the various. clutches .willbe briefly described.

:Referringfi-rst to the clutchon-the driveshaft :2l,:aperipherallygrooved clutch ring H is provided with internal teeth "and is adapted to. slide axially,onclutch-teeth 33 formed onan enlarged portion of the shaft. i'It vwillbe seen that when clutch ring ll isshiftedjrearwardly ;(to the right in Figure 3) from the position shownin this fig-- ure, the clutch ring engages clutch teeth 31.car-

'riedbythecluster-gear t t-and is effective to lock theclustergear-to thedriveshaft 2|. With the clutch ring 1 in the position shown in Figure 3,

however, theQcluster gearis notcoupled to the driveshaft.

Referring ,now .toithecountershaft 22, a clutch ring 72, when shifted .to .the:left fromtheposition hand, when the clutch ring 14 is shown in Figure 3, engages the clutch teeth 4'! on the gear 46 and the clutch teeth 44 on the gear 43. In this position the gears 43 and 46 are coupled together and rotate as a unit. With the clutch ring 12 in the position shown in Figure 3 the gears 43 and 46 rotate independently of each other and are not coupled together. The clutch rings H and '12 are operated in unison by a double fork 13 described more in detail hereinafter.

A similar clutch ring 14 is mounted upon the toothed clutch member 49 for axial sliding movement thereon. In Figure 3 the clutch ring 14 is shown in its central or neutral position. Inasmuch as the clutch member 49 is splined' tothe countershaft 22,-it will be seen that when the clutch ring (/4 is shifted forwardly to engage the clutch teeth 46 on the gear 46, the gear 46 will be locked 'to the countershaft 22. On the other shifted rearwardly into engagement with the clutch teeth 5| carried by the gear 50, the gear 50 will be locked to the countershaft 22. The clutch ring is shifted by a fork 16, to be described more in detail later.

With reference now to the driven shaft 23, a clutch ring 77 is slideably mounted upon the periphery of the toothed clutch member 6| and is actuated by a double fork 18. The clutch ring T! is shown in Figure 3 in its central or neutral position, and it will be seen that when it is shifted forwardly into engagement with the clutch teeth 59 on the gear 56 the latter gear will be coupled to the driven shaft 23.

Attention is now directed to the idler shaft 24. A clutch ring 19 is slideably mounted upon the periphery of the toothed clutch member 69 which in turn is splined to the hub 64 of the gear 66. The clutch ring 19 is adapted to be slideably moved by the double fork 18, and when shifted rearwardly engages clutch teeth 68 on gear 6'! to lock gears 66 and 61 together for rotation as a Shift pattern Referring briefly to the shift pattern shown in Figure 15 it will be noted that the gear ratios are divided between a low range and a high range of speed ratios. The low range includes first, second and fourth speeds forward and a reverse, while the high range includes third, fifth and sixth speeds forward. and a reverse.

Low range-First speed Selection between the low and high ranges of speed ratios is effected by actuation of the double fork 13 which simultaneously shifts clutch rings TI and i2. Shifting the clutch rings tothe left in Figure 3 or forwardly of the transmission, causes clutch ring 72 to straddle clutch. teeth 44 and 47 and to lock gears 43 and 46 together. For all speeds in the low range, therefore, the power flow begins through gear 32 on the driveshaft 2i and gears 43 and 46 on the countershaft 22. First speed is effected after the transmission'has been shifted into low range as previously described, by shifting clutch ring 74 to theright in Figure 3 so that the clutch ring straddles the teeth on the clutch member 49 and the clutch teeth 5! on the gear 50 to lock gear 56 to the countershaft 22.

The power flow in first speed is through the following gears in the order recited: gear 32 carried by driveshaft 2|, gear 43 rotatably (ill gear 38 on the cluster gear, the countershaft 22 by the 52 carried by the countergrally formed with gear 56 coupled to clutch ring 14, gear under heavy conditions, or with transplanters,

orchard sprayers, and other ing an extremely low speed.

Low range-Second speed Second speed is obtained simply by shifting the clutch ring 14 to the left to straddle the clutch teeth on clutch member 49 and clutch teeth 48 on the gear 46. Gear 46 is thus" coupled to the countershaft 22 and the power train is the same as in first speed except that the reduction afforded by the cluster gear 34 is omitted. The power flow for second speed is through gears 32, 43, 46, 52 and 62 to the driven shaft 23. A reduction of 64 to l is obtained in second speed with a tractor speed of 3.5 miles per hour at 1500 R. P. M. engine speed. This speed is the one most generally used for normal plowing.

Low rangeFourth speed The next highest low range speed is fourth, and this is effected by shifting the double fork 18 to the left in Figure 3 to shift clutch ring 11 to interconnect the clutch teeth on clutch member 6| with clutch teeth 59 on gear 58 and to therefore couple gear 58 to the driven shaft 23. The power flow from the driveshaft 2! to the driven shaft 23 for fourth speed is through and 58 to the driven shaft 23. Fourth speed gives a reduction of 38 to 1 and a tractor speed of six miles per hour and may be used for extremely light plowing or for tillage where a reasonably fast speed can be used without damage to crops, such as with spike tooth harrows and similar implements requirimplements.

Low range also includes a reverse speed reduction of 154 to 1 with a reverse tractor speed of 1.5 miles per hour. This is effected by shifting the double fork 16 to the right in Figure 3 to shift clutch ring I9 to couple together the clutch teeth on clutch member 69 and clutch teeth 68 on gear 61, thus locking gears 66 and 61 together for rotation as a unit. Inasmuch as gear 6! on the idler shaft 24 is in constant mesh with gear at on the countershaft 22, it will'be seen that this again brings the cluster gear 34 into the power train, the latter comprising the following gears in order: 32, 43, 46, 38, 39, 50, 67, 66, and 62 to the driven shaft 23. It will be seen that an extremely low reverse speed is thus obtained.

High mnge-Third, speed :cluster gear-v 344-130 the drivesh-aftl l l :thepreceding paragraph,

. .tring countershaftrflt gears-:.-66 sand: fi'l-stogether. i iromidriveshaftfi -.';ir;highirange speedsgand thence through gears 39,- 50,161; 66. and 62;.to the driven shaft;23.

aeees so ....thus directly! driren zby.=;the idriveshattl 2 I and. in- -I.aSmuGh 12,S theicluster gearacarriess-two gears--38 rand-e53 9 awariety Qt-speeds. can: be obtained .-by

: utilizing;gone;or theiothery-of. these gears in. the

T:-powerrtrain.xa

t The. lowest;-- speed in :high (1 isiefiected; withstheiclutch-fring H shaft 2 It to. the-rcluster gear 34, thence; through a s gears: 39:.and 501: the countershaft. .22, andlthen wfrom geanfiZk-om theicountershaf-tuto x gear: fizz-on the driven shaft I3HcTheJreduction-1in. third speed is 49 to 1..with. a tractor speed of 4.5, and this gear ratio issuitabl'efor all'plowing of a t nlightenmature:swhere .sadditionaltispeed;'zcan be r: :usedg.

L .High. v1'angeFifth "speed -7 Shifting 'clutch' ring 'll' Into the left 'Iobtains countershaft 22 through the clutch member 49, in

amannersimilar to" the shift'required in second speedof low range. irom'thedriveshaft i hto the'clustergear 34 but in this instanceis I from gear; gear to gear 4B," the "The power-flow is again 38 of the' cluster latterbeing coupled to the countershait 22 through the clutch member 49, and finally-throughgears 52.-and.B2 to the driven shaft 23. The reduction in fifth is 21 to 1 resultingih a-tractor speed at 1500 RIP. M. of 11 milesper hour; which is a suitable-speed for road i'tran'sport of tl'ie'tractor.

x H range -Sixth speed f'ihe fast'estiforward speed, or sixth; isefiectedv i'by' shifting'the double fork IS-to the'left in Figure'.3',fto shift clutch ring-11 and couple gear 8 to shaft "23,"the"power:"flow"now" being from driveshaft 12 It. to the ,clusteri'gear 34 and from'gear I, 38 on the clu'stergear; .to gear 46" which] freely rotates aboutthe countershaftzljand thence to gear 58 now coupled".Jtogthepdrivenshaitt23 by the "clutch' ring 'Il.

"Sixth speed gives atotal reduction of 12 to 1 and a tractor"speed"'-of18.6

miles per hour;- which*= Higlr"1'ange .-iRe'vers-e a: A rerersefispeed'i's. alsoiavailable inrhi'gh range; mandris effected by shiitingthe doublei tor-14x18; to

the --right; 1120 :shift. clutch -.ring l9"and=- couple The powerwflow. is t'to the cluster'gear 34; asin. all

.. It 'will be-.understood that the uses of thevariousgear ratios :briefiydiscussed above. are only 3-: given by way. of. example and that, various other uses-ifortheparticularratios exist. .The six forward gear ratios obtainable with the present transmission are ideally suited for various tractor operations; The two reverse ratiosobtainable, one-inflow range "and :the. other in high :range,

'1 simplify 1 gearshifting. since a reverse: speed is :"readilyobtainable regardless of. the particular :iorward speed in whichthetractor. is operating. ifxlnfthe'. majority-cot: instancespthe 110w: reverse. ob-

.ii'tainabletinrlowrange willzbe. the oneto be. used i when theftractoraisi'operatingi irrr'a low rangeafov" gear: Mi -to" the fiordsa fast transport 1 1 speedfordrivingthewtractor ontheroadwithout implements.

" :vwardrispeeck'ratio; nndathe higlrirewersefebtain- I ,able; inzihigh Jange;.yvi1l;-be;the mostssuitableire- :verse'saratio underrrtheia ircumstancesgzzexist'mg when: athertractomhasebeen; operating. inzone -of the high .rangezforward speed ratioss Whileithis .i simplifiea-the.i-gearshifiting; robviously, --.howeuer,

.- either .-reverse.-maytbeobtainedl-atsany 1 time. s

wing only utenheavyr' loads mayr be carried-since-tha gears are i all" mountedupon :short-shafts-. with a: relatively It. will: be; noted tthat-itheivarious; gear. ratios briefly discussedlaboves aretobtained-i-witir a :very compact transmission arrangement; incorporat- -,i gears; Furthermore; relatively a. short" distance betweeni-bearingsl i *Shift mechanism v The; construction L o...the-.=shift mechanism fifOI' the transmission will vbe. best..understoodnby referringfirstto Figures i land: 14. ..Adjac,ent..the

: :bottom of thetransmission. housing. l 2 is-- a lionvigitudinally: extending-;-shiiter-.rail 8l in :the form of. arod. At =itstforward endthe. sln'fterraih-M istslideablyrmount'e'd in abracket 82 integrally formed with the transmission housing tAtrits rearward end:the.\-shiiter-1rail extends.-.thrczugh an opening I 83 :in the intermediate I wall.- 3 lrivi of-ethe housing. .A series. :of" tthreeparcuate i-groovesm l .are. formed in the lowerezsurface or theashii-ter rail. 8 l near its. rearward -end;:to,-permitlthev rail to be indexedin ,three'longitudinally spaced-positions. The. indexing .is-accomplished byzaball 86 urged into engagement .with 'the.. notchese 84 by means of a spring: 81:; ,'.The-ba1l.86 andspring 31: are mountedi-inea-i bore 88' \-in:the=,-wall 3 l of the housing and are held}. therein .byzastud 89.

-Asabest seenvin Figures 4waindfiliyrthfimd0llble tone! 8 is mounted upon. theashiiter rail 8 t rbeing held thereon by a i set-. :-screwtfiflsands lockcnut 9 I ,The, double fork 18-has .bifurcated iportions 92 which arerredu'ced inrthickness and. areyadapted to i he received swithin rthex peripheral grooves formed in the clutch rings '11 and 19. It wilLbe apparent that longitudinal movement of the shifter rail 8| isv effective through. the shifter fork ":18" to simultaneouslw'shiftithe .'.clutch rings. 11

and 1a between three positions. 'The central position: places both clutches. in neutral; the ifor- "ward p'ositiomefiectsl.an engagement of" clutch ring. 11 and the rearward-position effectsan engagement ofjclutchiring l9.

Referring now to" Figure 5,"there' ismounted upon the lower shifter-*raiPBlg'fland held thereon byva set screw-.93, alug. 94. Thelug 94 visadapted tobealte'rnately engagedby a shifter.;.arm..or.an

, interlock bracket tdccntrol. the .longitudinalposition .oflthe shifter raiLB-l: and; the shifte'r. .fork I8. as .will, be .described more inu'detail. later. i

.. A pair rot-longitudinally extending. shifter.- rails 96 and 9 Lare. mounted adjacent ltheiuppenportion I of the transmission housing; l2 ,..,the rrails beingslideable attheir. oppositeends in thev walls 28 and 3t oiithetransmission.housing.l2.. L'Ihe .rearwardend ofhtheishifterarail 96 :is formedwith a series lof three-.arcuate; notches 98 a arranged for indexing/engagement with a ball-J9. held against the rail bya spring. l0.l.--- As seen. in Elig- 2103 urged against-the-rail-by aspring urev 4A, the rearward .end of. shifter rail Slis provided with two-longitudinally spaced notches ,1 02 arranged for indexing engagement-with: asbalI As shown in Figures 4 and: 14, the iorkfjlfi is rigidly mounted uponthe shi-iter-rail .96 by means of a set: screw-:l OBTLand: a lock nut (10.1. Thew'iork 16 has bifurcatedaportionse. I 081 reduced in.-.thick- :nesszandeengageablelwithinithezperipheralzgroove formed in shifter ring 14 which in turn is slideably mounted upon the clutch member 49.

Near its forward end the shifter rail 96 carries a shifter lug I09, Figure 5, rigidly mounted the clutch ring TM.

Referring now to Figure 5, the shifter rail 9'3 carries the double shifter fork 73, the latter being means of a set screw H3 and a lock nut H4. The shifter fork I3 has hi furcated portions IIB reduced in thickness to fit the aboveupper end the shifter shaft I2I extends through a bushing I23 pressed transmission cover I24.

The extreme upper end of the shifter shaft I 2i is keyed to a shift lever I26 extending upwardly rearwardly and inwardly toward the drivers position. The upper end of the gearshift lever i26 carries a knob I 21 for operation by the driver. The lower portion of the gearshift lever I26 is formed in the shape of an inverted cup and houses the upper end of a coil spring I28 with the upper end of the spring bearing against a shoulder on the gearshift lever and the lower end resting upon a washer I 29 seated upon the bushing I23. A sheet metal shield I3I is cup shaped portion of and encloses the upper end of the bushing I23 to protect the assembly from the weather.

It will be apparent from the foregoing that the shifter shaft I2I is mounted in the transmission for rotary movement and also for vertical sliding movement, under the control of the driver is indicated on a shift pattern plate I32 shown diagrammatically in Figure 4. As best seen in Figure 15, the plate I33 which in turn is upper surface of the ing in position to be viewed by the vehicle operator. The plate I32 has engraved or suitably displayed thereon a shift pattern I34 indicating the six forward speed positions and the two reverse speed positions, as well as the two neutral positions.

Mounted upon the upper end of the shifter shaft I2I, Figure 4, is a pointer I33 suitably secured thereon by a nut I37. The forward end of the pointer is positioned closely adjacent the plate I32 and as the gearshift lever I26 and the shifter shaft I2I are moved vertically and angularly between the various indexed positions, the particular position is indicated on the shift pattern I 3 5 by the pointer its, enabling the operator to not only ascertain the particular speed ratio in which the tractor is operating, but also to determine the movement necessary to shift to any other desired speed ratio.

As best seen in Figure 5, a of shifter arms IM and I52 are suitably welded or brazed to the shifter shaft I2I. The arm MI is adapted to be engaged with the lugs me and II! to shift the upper shifter rails and 97, while the shifter arm M2 is adapted. to be engaged with the lug 94 to shift the lower shifter rail 8I.

Figures 8 and 8A show the upper shifter arm Hit in engagement with the lug I99 carried by the shifter rail at. The lug I69 has a pair of notches I43 and I44 adapted to receive the enlarged end portion I lt of the shifter arm I M. Depending upon the angular position of the shifter shaft I2I the arm IdI engages the notch I 43 for low range speeds and the notch M4 for high range speeds.

Figures 9 and 9A show the upper arm I 4| in engagement with a notch I 41 formed in the lug I I1 carried by the fork 73. Angular movement of the shifter shaft I2I moves the fork l3 and shifter rail 57 longitudinally between the positions shown in Figures 9 and 9A.

Figures 10 and 10A show the lower shifter arm M2 engaging the lug 94 on the shifter rail 8I. The lug 94 has a pair of notches I 48 and I49, the former being engaged by the enlarged head I5I of the arm I42 for low range operation and the latter being engaged by the arm for high range operation.

To prevent the forks and lugs from being in advertently shifted from their neutral positions while one particular fork and lug is being moved by the adjacent shifter arm, upper and lower interlock brackets I52 and I53 are provided. These two brackets are identical in construction, and differ only in that they are inverted during assembly. Consequently only one will be described in detail.

The lower bracket I53 is best shown in Figures 4, 5 and 12, and comprises a crescent shaped member having parallel bores I54 formed. in its bifurcated end portions. The bores I54 in the bifurcated end portions of the interlock brackets slideably receive rods I56 and I5! vertically mounted in the transmission housing. The lower ends of the rods are seated in the boss I22 integrally formed with the transmission casing I2 while the upper ends arereceived within bores formed in a bracket I58. The bracket I58 has legs I 59 secured to the upper flange of the transmission casing I2 by means of bolts IBI.

Within the notches I48 and lug 94 carried on the shifter rail SI. With the interlock bracket I53 and the lug 94 thus engaged, longitudinal movement of the shifter rail Ill and the fork 18 carried thereby is prevented.

Referring now to Figure 5 it will be seen that the inwardly projecting intermediate portion of the interlock bracket I53 is formed with a groove I64 through which the shifter arm I42 extends. The separated portions of the flanges I 52 and I63 thus straddle the shifter arm I42. Inasmuch as the shifter arm I42 is secured to the vertical shifter shaft I2 I, vertical movement of the shaft M9 formed in the 'aeieogsso;

results in corresponding verti'cali movement 'iof the' interlock bracket I53, the latter freely sliding on the rods I56 and I51.

As previously mentioned; the upper interlock bracket I52 is identical in construction to the lower bracket I53 but is mounted finzinverted position, and straddles-the shifter arm MI. The

shaft I2 I issiprov'ided upper end of the shifter with an annular groove lfifi' arrangedxto be indexed by a ball I61 urged against the shaft by a spring I68. Engagement betweenthe ball 1161 and the groove I86 is effected when the shaft is in its central position 1 at which time the trans.

mission is in neutral.

In addition to providing interlock mechanism effective Ito'prevent the transmissionfrom being shifted: inadvertently, -.means" are :provided. for

preventing the'starter from being 'actuatedxexcept'when the transmission is means comprises at having a hub' encirclingwtherishifter shaft. :I2 I: The: bracket 1 69. "is 1 positioned -.longitudinallys :of

the shaft-betweenithe upper-portion of the'bracket 7 I58 and a retaining plate I1I held-bytaimeans of bolts 12. adjacent the. lower portion of: outwardly extending integral: flanges 11 300i the bracket KI 58. Whilethe .starter interlock. bracket 169 is freely in neutral. This starter interlock. bracket 1.69

rotatably lmountedaon :the shifter fshaft r I2 I it tis constrainedltosmove. angularly with the shaft by means of downwardly extendingrbifurcati'ons I14 straddlingran. intermediateaportion of the; upper shifteri. arm: :"I 4 I.

Also integrally formed-:withxthe starter: intere lock 1- brackets I69.:':=iss,a horizontally extending flange I516 best seen in Figur e.::13 asibeing: quadrantxshaped. "Them-flange I:16 is;provided .withx andt' I18 a pair of angularly spaced holes I11 suitablymositionedxfor engagement with a downwardlywpro'jeating-pin I19 of a'starterubutton -IsI 1 when the transmissiomis in neutral. Inasmuch as 'the transmission has tions; one

when it is in neutral, high timesthe flange I216 ofthe interlock'bracket-I69 prevents: depression .of: the starter. button two; indexed neutral posi- .for; low range 1 and another. for 'high; rangepzthentwo. holes 111; and .I18 .arerhecessary to i-permit the; starter to 'beractuated-wwhen the transmissiomis neutral, .low: range; andv alsov Iange.,15tAtIIa11 other intercepting; the 'movement-ofwthe pin. I18, thus preventing the starter ifrom bei-ng operated::ex-,,-

cept': when the drive -to the rear wheelsidisconnectemi 'Shiftmechanism -Operation the .transmission'cisin; neutrahandi 1 As previously mentioned, the, shifter shaft I2 I1.

is adapted to. be reciprocated' vertically and also moved .angularly by i manipulation of the; gear-.

shift lever I25 by the driver.

Figures 5,. 6 and central, tanddowermost positions of :the vertical;

shifter. shaft; I2I. Reference is firstumadetto Figure 6, showing the:

vertical-shifter shaft, in which positiontheindex The shaft maybe i reciprocated .verticallybetween three; :positions.

'1 respectively show thelupper,

central, positiomof vthev ball I 69,-. is in engagement with-the annular groove I66 formed in. the-upper portion ofv the shaft.

sumcient to holdthe shaft. in this. position, and

- 65 The engagement between the ball and groove is to overcome the tendency of-the springvl-28 at the upper end of wardly. Referring.

as 'toFigure' 6, when the shifter shaft II2I. is in theshaf-t .to, shift the-shafteupw.

to Figures -9 .and 9A asv ,well

its central or neutral positionthe upper. arm ML 5 I engages the notch thedo'uble fork 13. can be manipulated" tc-move' I41'in' the lug I'I1 carried. by h At this" time the leverIZB the ShifterShaft 75 cablyiindicated' upon the shift pattern 15,. by the pointer -I 36,.;and loear the indices N1} for-neutral, low 'range, and Na .forfcneutrlalir high I2 I angularly. Movement 'in" a counterclockwise rail '91- 'forwardly of direction shifts the shifter the transmission to the position shown in Figure 9, whileangular movementin a clockwise direcrail rearwardly to the These two posi tions areindexed by means of the notches lln at the rearward end iof=- the rail 91 as shown in Figure 4A. In the .posi H 7 tion shifts isthe :fork and position shown Jin'Figure .9A.

andballs I83 arranged tion shown in Figure '9 the shifter shaft -I2I is located in its neutral positiontfor i .lown-rangepperation whilevin therposition shown inFigure QA: the. shaft .is positioned in'.neutral position stor These positions are suit 1 "I314; Figure high range :op'erati'on;

range."

Withthervertical shifter shaft .12 I. in its central: or neutral position; as rshowniin Figure; 6, 'and neutral, :low range; or neutral', high.:range;.rit is desirable to prevent inadvertent shifting :of the; shifter. rails .1 This is accomplishedl byi'the rupper and lower interlock brackets .I-52i2andn f53: re

with. the transmission thus in either 95- and-'- BI.

spectively which "engage the lugsa-Illsziandeifl mounted uponzthe shifter rails 96 and 58 I respeoe-w I tively. Inasmuch as. the. non-rotatable rmter-x lock brackets I 52 :and153: are .engagedirespectively." with the lugs "I09 *and 94,:inadvertent ,operati'on w of the rails '96. and: 8 I': :is iprleventedp...

From: the neutral position shown: in Figures .9- be :shiftedJtoI firsta z and second; speeds; in low range and: to thirdand..- fiftlfz'SPEBdS in high range by; shifting cal shifter shaft upwardly toiits uppermost: posi- 1 and 9A, thetransmissi'on-zmay tion' and then rotating; it reitheru clockwiseoeior counterclockwise izdependingeupon the -.particular speed-range desired. Referencedszmade to Figure 5 and to Figuresy8andSAflshowingatheuppermost positionaofithe shifter shaft. position the. upper :shiftertarm'rl 4 l engagesieither 5. M3- or the notch-14 ivv in the:lug:169:.on theeshifterti'rail'fi 6 dependingmponx:whether .the transmission IiS being shiftedfrom: :neutral, ;low

range. or neutral; high ranger;

Figure the upp r; shift arm I 4 I in neutral'pl'owr range,

tion atthis time:

As seen in Figure 8A, neutral, high-range, the .shifter arm-I 4 I1 rengagestheenotchr I Hi inrtherlug- 'I iiS-Tomthe -shifter-rail: 965; Clockwise movement of the shifter shaft: I2 I is effective to shiftl. the transmissioninto third speed while couhterclock-- wise 'm'ovement of the shaft shifts the transmis- -gsion into fifth speed in the manner described earlier in the specific'ationp It will be noted fromliigure 5 that with the shifter shaft-I2I in its uppermoshpositiontheinterlockbraokets -I 52" and -'I 53 are in engagement *withthelugs II1 'and'fll-respectively to hold the theiillrtia i Imthenuppermost 2-:

8- 'shows the. position-zforzz neutral; 210w range; and it-will l'be'seen' that subsequent angular: movement of awe-gearshift leveriandithe :shifter 'r shaftri 2 I- fromtthe neutral; position: ffGCtS-Wflli z. ous speed ranges: Withuthe :shifterushaft-andu shifterrails 91 and Ill against inadvertent movement.

Reference is now made to Figure 7 whichshows the shifter shaft I 2| in its lower position. In this position th upper interlock bracket I52 engages the upper lugs I09 and I I l to prevent inadvertent shifting of the shifter shafts 95 and 9'! respectively. The lower shift arm I42 engages the lug 94 to permit the lower shifter rail as to be shifted longitudinally upon rotary movement of the shifter shaft. Figure 1!) shows the angular posi tion of the shifter shaft I2I and the arm [:32 for neutral, low range, with the end I5! of the arm in engagement with the notch hit of the lug 9:3 on the shifter rail 8|. clockwise movement of the shaft and arm shifts the transmission to reverse, low range, while counterclockwise movement from the neutral position shifts the transmission to fourth speed forward. Figure 10A shows the shifter shaft I2 I and lower arm I42 in position for neutral, high range, with the end of the arm in engagement with the notch I 49 of the lug. From this position the transmission may be shifted into reverse, high range, by

clockwise movement of the shaft and into sixth speed forward by counterclockwise movement of the shaft.

As previously mentioned the various gear ratios are indicated in Figure upon the shift pattern I 34 and it will be readily select the particular ratio desired and make the necessary shift by reciprocating the gearshift lever vertically and rotating it until the pointer I36 is directed toward the desired index. It will be seen that the shift mechanism is com pactly located at one side of the transmission housing and contains a minimum of parts, and furthermore that the interlock mechanism automatically permits one shifter rail to be shifted while preventing movement of the other two shifter rails so that operation of the transmission will be positive at all times.

We claim:

1. In a variable speed power transmission, in combination, a driveshaft, a countershaft and a driven shaft, a drive gear carried by said driveshaft, a two element cluster gear rotatably mounted on said driveshaft, first, second and third gears rotatably mounted on said countershaft in constant mesh respectively with said drive gear and the two elements of said cluster gear, clutch means selectively connecting said cluster gear to said driveshaft, additional clutch means selectively coupling said first, second and third gears to each other and to said countershaft, and gearing between said countershaft and said driven shaft.

2. In a variable speed power transmission, in combination, a driveshaft, a countershaft and a driven shaft, a drive gear carried by said driveshaft, a two element cluster gear rotatably mounted on said driveshaft, a first gear rotatably mounted on said countershaft in constant mesh with said drive gear, second and third gears rotatably mounted on said countershaft in constant mesh with the two gear elements of said cluster gear, gearing between said countershaft and said driven shaft, clutch means selectively connecting either said second gear or said third gear to said countershaft, second clutch means selectively connecting said cluster gear to said driveshaft to transmit power from said driveshaft through said cluster gear to either said second or said third gear depending upon which of the latter gears is connected to said countershaft by said first clutch It will be apparent that apparent that the driver can means, and third. clutch means selectively con-" necting said first and second gears together to transmit power from said driveshaft and the drive gear carried thereon through said first and second gears to said cluster gear and thence to said third gear and said countershaft.

3r1he structure defined by claim 2 which is further characterized in that means are for. simultaneously operating said second and third clutch means, said operating means being effective when shifted in one direction to operate the second clutch means to couple the cluster gear to the driveshaft and effective when shifted in the opposite direction to operate said third clutch means to connect said first and second gears together.

4. The structure defined by claim 2 which is further characterized in that said gearing between said countershaft and said driven shaft comprises a fourth gear shaft for rotation therewith and in constant mesh with a gear fixed to said driven shaft, another gear rotatably mounted on said driven shaft and constantly meshing with the second gear on said countershaft, and additional clutch means selectively connecting said other gear on the driven shaft to said driven shaft to provide an alternate power path from said countershaft to said driven shaft.

5. The structure defined by claim 2 which is further characterized in that the gearing between the countershaft and the driven shaft comprises a pair of gears in constant mesh with each other each fixably mounted upon their respective shafts, an idler shaft, a pair of reverse gears rotatably mounted upon said idler shaft, one of said reverse gears being arranged in constant mesh with the third gear on said countershaft and the other of said reverse gears being arranged in constant mesh with the gear fixed to said driven shaft, and additional clutch means selectively coupling said reverse gears together to transmit power to said driven shaft in reverse direction.

6. In a variable speed power transmission, having a driveshaft, a countershaft, an idler shaft and a driven shaft, selectively operable gearing between said driveshaft and said countershaft, a gear rotatably mounted upon said driven shaft and arranged in constant mesh with one of the gears on said countershaft, a gear rotatably mounted upon said idler shaft and in constant mesh with another of the gears on said countershaft, a second gear rotatably mounted upon said idler shaft, a second gear fixed to said driven shaft in constant mesh with the second gear .on said idler shaft, clutch means for selectively coupling the first gear on the driven shaft to the driven shaft, additional clutch means for selectively coupling the two gears on said idler shaft to each other, and common operating means for said two clutch means operable when shifted in one direction to engage the first-named clutch means and when shifted in the opposite direction to engage the secondnamed clutch means.

7. In a variable speed power transmission, in combination, a driveshaft and a second shaft, a drive gear carried by said driveshaft, a twoelement cluster gear rotatably mounted on said driveshaft, first, second and third gears rotatably mounted on said second shaft in constant mesh respectively with said drive gear and the two elements of said cluster gear, clutch means selectively connecting said cluster gear to said provided fixed to said counter- 

